The total set of the environments in which a sound can occur in a given language. Two sounds may have identical environments and are said to be in parallel distribution, or have partially similar distributions (overlapping distribution). If, however, two sounds may never occur in similar environments they are said to be in complementary distribution.

Below is a short list of pairs of sounds in complementary distribution in various languages.

  • General British English: l ~ ɫ
  • Japanese: ɸ ~ h
  • Castilian Spanish: d ~ ð